This is the part of the mod that I was most nervous about, the top metal case would obviously prove to be the most difficult task to overcome due to the legends and rainbow stripe graphic. After much head scratching I decided NOT to spray it white and apply some form of transfers for the legends, but instead to re-create the whole metal top layer in a DTP package and print it out on adhesive vinyl.

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Required Items

There are a number of items that will be required for this part of the mod, if you require information on any products used, feel free to contact me.

  • Software to design the keyboard layout, I used iStudio Publisher on the Macintosh, but any graphics software with layer support should work.
  • A flatbed image scanner.
  • Vinyl adhesive paper.
  • An inkjet printer to print onto the vinyl paper.
  • A sharp modelling knife.
  • Crystal clear gloss spray to protect the surface.
  • Some sticky tape.
  • A 5 gigawatt crystalline laser spire.
  • A vice or some other method to flatten any large dents in the metal casing.
  • A hammer to lightly tap out smaller dents.

It's worth noting that one of the above items doesn't exist.

The Mod

This part of the Just Speccy modification is pretty lengthy, it's a little complex but not overly difficult so take your time.

1. Preparing the top metal casing

The rubber key ZX Spectrum 48K at the time of writing (July 2015) is about 33 years old, as such it is likely that there may be some damage to the top metal casing, this would have to be dealt with before applying the vinyl sheet.

  • The top case was carefully removed from the ZX Spectrum using a modelling knife blade to ease it away from the plastic and sticky tape fixings. Take care not to damage the plastic case.

  • Any dents or kinks were flattened using a vice, then the metal casing was placed face down on a table and any imperfections lightly tapped out with a hammer.

  • The surface of the top case was then finely sanded to remove any rough spots that would show through the vinyl. This will leave the plate looking terrible, but don't forget we are covering the entire surface with a sheet of vinyl and I just needed it to feel smooth to the touch.

Top case after dents removed and sanded.

2. Mapping out the key template

  • The top metal case was placed face down onto an A4 sheet of paper and taped into place, the keys were then traced onto the paper.

  • The case and paper were then separated and the tracing was scanned into the computer using an image scanner set to A4 landscape 300dpi.

  • A new A4 300dpi landscape project was created in iStudio Publisher, the scanned image was imported and resized to exactly match the pages dimensions. The hope was that when the project is printed, it will be the correct size.

  • The legends were then added to the iStudio project to match the ZX-Spectrum layout and then the template layer hidden.

  • The project was then test printed onto standard A4 paper and held up to a light with the spectrum KB case behind in order to check the keyhole positions, they matched perfectly!

  • The overlay was then printed onto vinyl adhesive paper.

    The printout on the vinyl paper is incredibly volatile, it is easy to rub off the legends or accidentally mark the surface. Take extra care when handling and applying the paper to the case, don't let any adhesive paper come into contact with the newly printed surface. It took me 8 attempts to get this right without damaging the surface, take it from me you need to treat the surface with kid gloves at this stage of the mod.

Printed overlay for keyboard.

3. Applying the vinyl

  • Next came the problem of correctly positioning the overlay on the casing, I decided to again hold the printout up to the light with the casing behind it, the correct position was found and both the case and the vinyl were carefully placed face down on a cutting surface. The bottom edge of the paper was then cut and the backing of the vinyl was peeled; the casing was then placed on a flat surface facing upwards. The vinyl was horizontally aligned with the casing (I used the word BEEP on the casing) and the bottom of the vinyl offered up to the bottom of the case, carefully the vinyl was placed onto the casing. The edges were cut off using a modeling knife.

  • The casing with the newly covered vinyl was then placed upside down on some clean paper and taped in place, the paper I used was the backing that had been peeled from the vinyl as one surface is smooth, slippy and is ideally suited not to cause any friction. This point of step is to protect the surface from damage whilst cutting out the keyholes.

The top metal casing with overlay applied.

4. Cutting out the keyholes

  • To cut out the keyholes, a criss cross from corner to corner was firstly cut using a modelling knife.

  • The edges were then cut, I found it easier to cut one side of all the keys, then repeat for each side.

  • All pieces were then removed.

A keyhole showing the cuts made to facilitate easy removal of the excess vinyl.

5. Protecting the vinyl

Two layers of a crystal clear gloss spray was used to coat the surface and left to dry for 24 hours; this not only protected the vinyl, but had the nice unexpected result of giving the surface an almost metallic look and feel.

Top metal case after protective spray coating.

6. Tidying up the keyholes.

Using a sharp modeling knife, the keys were tidied up by slicing around the inside of the keyholes; you literally cannot go wrong here as the metal structure of the top case guides the cutting knife. Hold the metal case upright and insert the modeling knife up from underneath, that way if you have an accident only the unseen bottom of the case gets scratched, also the blood will drip away from your shiney new top layer!

Keyholes after tidy up.

Final thoughts

Although the top case modification seemed daunting, in the end it turned out to be quite easy. The only major problem I encountered was due to my lack of experience with working with the vinyl adhesive paper. I didn't realise how delicate the surface was and I damaged the print on numerous occasions, which meant I had to discard that layer and apply another one. Once or twice I had alignment problems but this was minor when compared to accidental damage.

The final result was stunning, the protective coating really did give the whole top case a metallic feel and I would even go as far as to say that this layer is now more robust than the original black ZX Spectrum silk screen layer.

Just one more point, it may be possible to print out the overlay onto normal thin paper and then use a spray glue to apply it to the top case, the protective layer may then give it the relevant coating. This would obviously bypass all the hassle I had with accidental damage, but as this method is untested I cannot foresee what problems may arise. If you managed to successfully use this method then I would love to hear from you.